Regulating means for independently fired superheaters



Oct. 10, 1933. A. HUET 1,929,890

REGULATING MEANS FOR INDEPENDENTLY FIRED SUPERHEATERS Filed Aug. 30, 1930 4/ INVENTOR Andr H uet 2/ BY 7// ATTORNEY Patented Oct. 10, 1933 UNITED S ATES PATENT oFF c Application August 30, 1936, Serial No. 478,936,

and in France April 25, 1930 3 p 2 Claims.

The present invention has for its object the provision of an improved multiple superheater operating on the recuperative principle and comprising several constituent superheaters delivering fluid at different temperatures. The tubes of these superheaters are arranged in chambers traversed in succession by the heating fluid.

The apparatus has particular application in installations for superheating steam to be used in multiple expansion steam engines. In these cases it is desirable to reheat the steam between the difierent expansion stages. One of the features'of this super-heater lies in the arrangement of the passages whereby it becomes possible to return the hot gases for further use either between the source of heat and the successive superheater chambers or in part in each of these difierent places.

A further feature of the superheater lies in the joining of the gas chambers whereby all or part of the hot gases can be passed either from the first superheater chamber to the fan or from the same chamber to one of the other chambers of the superheater, by passing the intermediate 5 chambers. The invention comprises also the arrangement of thermostats acting on dampers placed in the said passages or in the fan, these thermostats being placed in the superheated steam header and at points in the passages where the temperature is to be limited.

The description which follows and which refers to the accompanying drawing and which is given by way of example will make it clear how the invention can be carried out.

Fig. 1 is a longitudinal section of the superheater; Fig. 2 is a plan view; Fig. 3 is a section on line 33 of Fig. 1.

In the combustion chamber 1 there are generated from any heat source desired hot gases which flow by the passage 2 to the mixing chamher 3, thence successively into the superheating chambers 4, 6 and 8, each of which is divided into two parts by the baffles 5, 7 and 9 thereby forcing the gases to follow in each of the chambers first an upward and then a downward pass.

At the exit from the chamber 8, the gases traverse a conduit 10 and are delivered to a fan 11 which forces them partly through the conduit 13 to the air heater 14 whence they escape through 15 to the stack and partly by a conduit 16 and the adjoining conduit 17 to the passage 2 to be mixed in the chamber 3 to the new hot gases coming from the combustion chamber 1.

A damper 18 regulates the proportion of the gases forced by the fan 11 into the conduit 16.

The fresh air for combustion enters through w the opening 19 into the air heater 14, and after having absorbed a part of the heat introduced by the conduit 13 flows by the conduit 20 and the passage 21 toward the combustion chamber 1.

.perheaters the saturated steam header is the one further from thesource of heat so that the steam to be superheated is circulated in the tubes or elements in counter-current to the heating gases. From the conduit or passage 16 there is branched 7 a conduit 28 provided with a damper 29 connecting the passage 16 to the entrance of the super heating chamber 6. From the passage 16 there branches also a conduit 30 equipped with a damper and connecting the passage 16 to the entrance of the'superheater chamber. J

In the header 25 for the superheated steam there is installed a thermostat 32 by means of which, through the connection 33, including any intermediate action such as an electric. relay, the damper 29 can be opened or closed. Similarly, in the header 27 for superheated steam, there is installed a thermostat 34 regulating through v the connection 35 the opening or closing of the damper 31. These two thermostats are so adjusted that in the respective superheated steam headers in which they are installed, the desired temperature for the use to which the superheated steam is to be put is maintained. When the temperature exceeds the maximum which has been decided on, they open respectively the dampers 29 or 31 admitting into the corresponding superheating chambers a certain quantity of gas which has already been utilized and which is forced by the fan. This gas is mixed with the hotter gases coming from the superheater chamber 4.; I When, on the other hand, the temperature of the steam in the headers drops below the minimum decided on, the thermostats close the dampers 29 and 31 respectively and thereby interrupt or reduce the admission into the corresponding superheating chambers of the gases that have already been used.

In addition, there is provided a passage 3'7 communicating through the opening 36 with the exit of the superheating chamber 4 and provided at any desired point with a damper 38 and opening at 39 to the exit of the superheating chamber 8 so that a part of the gases leaving the chamber 4 may be discharged direct to the fan 11 through the conduit 10 without passing through the superheating chambers 6 and 8.

There is also provided a further passage 41 equipped with a damper 42 and communicating through the opening 40 with the exit of the superheating chamber 4 on the one end and with the entrance of the superheating chamber 8 on the other hand whereby it is possible to direct a portion of the hot gases from the chamber 4 directly to the chamber 8 without passing through the chamber 6. 4

It is evident that modifications may be made in the arrangement described by way of example without losing the spirit of the invention. For example, the number of superheaters may be other than three. One or another of the passages 3'7 and 41, or both of them, may be omitted and finally the air preheater 14 may be omitted and the gases coming through the conduit 13 may be sent directly to the stack.

What I claim is:

1. A superheater having a conduit for heating gases and containing superheater elements, means for reintroducing gases which have been used in heating at least a portion of said elements at a point at which the gas temperature has been reduced by contact with said elements but is higher than that of the reintroduced gas, and means whereby a portion of the heating gases may be withdrawn from said conduit after they have passed over only a portion of said elements.

2. The combination of a superheater as set forth in claim 1 with means for returning a portion of the withdrawn gases to the conduit at a point such that said portion passes over some of the superheating surface.

ANDRE I-IUET. 

